The human brain is indeed a remarkable thing. It is capable of storing and processing such a wide range of information that even a supercomputer would shy away when compared to it. But due to the virtual explosion of information, our memories have become very selective.
This means that we cannot recollect everything that we hear or see. Do not trust your memory too much when it comes to chatting over the net. You might meet a lot of people over the net and you might chat with a couple of them. So eventually it might become difficult to remember all of them and their details as well.
Or even worse than that is that you might become confused and mix up details. It would look bad for you if you call a person the wrong name, or ask the person the wrong details. In such cases where you have been chatting with a number of persons, for heavens sake jot down the details about each person separately or create separate files for each person ad store them in your computer.
When you add them to your friends list use handles or nicknames that can help you remember the person the moment you start chatting at a later date.Now, in case you do not really remember the person, then it is unadvisable to play the guessing game. The other person might get very offended if you say something like, “Is it Sarah or Mary?”
In such cases when you have a genuine lapse of memory, the best thing to do is to be honest with the person and say, “I know we chatted the other day, but Im terribly sorry, can you please refresh my memory about you?”